[1] Res Inst Brain & Blood Vessels, Dept Radiol & Nucl Med, Akita, Japan
[2] Tohoku Univ, Course Radiol Technol, Hlth Sci, Grad Sch Med, Sendai, Miyagi, Japan
[3] Univ Occupat & Environm Hlth, Inst Ind Ecol Sci, Dept Radiol Hlth Sci, Kitakyushu, Fukuoka, Japan
[4] Akita Med Ctr, Dept Cardiol, Akita, Japan
[5] Res Inst Brain & Blood Vessels, Div Internal Med, Dept Cardiol, Akita, Japan
[6] Aidu Chuo Hosp, Dept Cardiol, Aiduwakamatsu, Japan